


July 7th

by Lafeae



Series: Brotherhood [19]
Category: Yu-Gi-Oh!
Genre: Aged-Up Character(s), Becoming an Adult, Birthday, Fluff, Gen, writing letters
Language: English
Status: Completed
Published: 2018-06-25
Updated: 2018-06-25
Packaged: 2019-05-28 05:50:48
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,531
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15042155
Author URL: https://archiveofourown.org/users/Lafeae/pseuds/Lafeae
Summary: Mokuba’s turning eighteen years old. Kaiba’s having a hard time coping with the idea that he’s not a child anymore.





	July 7th

**Author's Note:**

> This took way longer than expected...because I had something else completely written out. xD and then hated it. So this was what I choose instead. Enjoy!

3:42 AM

~~_There comes a time when I_ ~~

~~_I have watched you grow into_ ~~

~~_I never thought that I would see_ ~~

~~_Eighteen is one of those ages that you only come upon once and I_ ~~

Kaiba sighed, another piece of letterhead stationary crumbled beneath his palm and thrown into a wastebasket with all the rest. His hands ran through his hair and pushed the bangs a back.

He still had many hours before Mokuba even thought about waking up, but for once in his life, Kaiba Seto couldn't think of the right words to address the adolescent. No, the adult. Cards didn't cut it—cheap sentimentality, mass produced with little thought. Even if Mokuba adored those he received from the KaibaCorp office staff.

The pen touched paper again, scratching away, until he drew a thick and solid line, ink bleeding from the tip.

Into the wastebasket.

—

7:57 AM

Kaiba's toes had a way of dragging when he was tired, his feet dropping more acutely, precise. Mokuba called it a 'runway walk' to confuse the masses when Kaiba's hours of wake had overtook sleep.

This was such a time, pressing the door of Mokuba's bedroom open, countered with careful tiptoes to not wake the slumbering troll. Why would he be awake at this hour?

A chair was pulled through the abhorrent mess that Mokuba called his room. A note to send the staff in, an excuse to wake him up.

The covers were pulled back, the grown mass of teen (adult?) and hair balled up all the same as he did when he was three, or five, or ten. He never changed. A hand pressed to Mokuba's back, and he shifted into it. Kaiba slumped forward against the edge of the bed, head in his arms. A small nap wouldn't hurt. There was no work today, no. It was forbidden by Mokuba.

They had to have be selfish, together, on this day. They made the world adhere to their childish whims and fancies. And Kaiba was just fine with that.

—

12:18 PM

Mokuba awoke, though not of his own volition. The housekeeping staff opened up his curtains, washing the room in warm July sunlight. His windows were opened; cicadas buzzed in the distance. He blinked the last few grains of sleep from his eyes and pushed himself up in bed.

"Good afternoon, Mokuba-chan. Happy eighteenth," the maid said. "Seto-sama is downstairs waiting for you."

"Waiting...?" Mokuba groaned. His fingers were used as a comb through his hair, brushing frazzled clumps down where the July humidity was already punishing him. It was braided up to a manageable mess. A shirt was snatched up from the floor before the housekeeper threw it into the hamper.

Pants were yanked on as he stepped out into the hall, stretching his arms up over his head, ribs aching and shoulders popping. Staff passed in front of him, bowing and chirping birthday wishes. They were greeted with smiles from the Mokuba, hardly awake and, though excited, almost forgetting it was his birthday.

The last few weeks had been nothing but work, tailing Kaiba place to place, meeting to meeting, refusing to stop even though his brother would urge him otherwise. "You don't want to develop my bad habits," Kaiba said over coffee.

Mokuba found himself smiling beyond the rim of his own mug, vision tracing the dark circles under his brother's eyes. He wanted to be able to be the person his brother could lean on, the person he could rest against when he became exhausted. At eighteen years old, he felt much more official as the KaibaCorp vice-president.

Sleeping in wasn't the way to do it. It was already noon, the day felt so wasted. But that was how it was, regardless of the day of the week his birthday fell on. He would sleep in, forgo school, work, responsibility. The one day of the year he could urge Kaiba to do the same. And anything else, really.

"You really need a haircut," Kaiba said, peering up from the couch as Mokuba descended. "Did you shower?"

Mokuba stuck out his tongue. "They said you were waiting."

"I've waited this long, ten more minutes is inconsequential."

"Nii-sama—!"Mokuba groaned, stopping at the threshold into of the parlour. "It's my birthday!"

"And?"

"And I can look however I want in my ID photo!"

"Shower," Kaiba said. Another low, troll-like groan. "And use soap!"

A slam of a door. Kaiba bit back a laugh, returning to his e-mail, sending off the last before Mokuba returned and scolded him. The letter he had spent so long penning was set on the coffee table, folded into perfect thirds.

—

2:07 PM

A yellow car zoomed like a blur along the test track, the sound a half second behind it.

"It really is the fastest on the market right now, Kaiba-sama," the salesman said. "She's a gem a car. I think it suits the fukushachou perfectly."

Isono had stepped between his employer and the salesman. "He seems to be enjoying himself," the suit remarked. "Such a simple request."

"To race?" Kaiba asked, incredulous.

"He could have asked you to buy the car," Isono said.

Kaiba sighed, eyes following the car's next lap. "I suppose. Why he gets practice laps, I'm not sure."

"I think you have a few years on him, sir."

Kaiba leaned his head back, brow raised to Isono before a wily grin appeared for a fraction of a moment. "And he has years of sleep on me," Kaiba said. The car came to a stop, a strong tang of rubber assaulting all senses. Mokuba popped out of the car, leaning against the roof.

"Ready to lose, nii-sama?"

"Not likely to happen. I'd hate to make you upset on your birthday."

"I'm gonna win and you know it!" Mokuba announced.

"And what do I owe you if you lose?" Kaiba asked, making his way to the car that he was going to be using for the race. Mokuba pressed his thumbs together, thinking.

"Dinner with all the friends?" Mokuba asked.

"Fair. And if you win?"

"Still dinner! But you have to lead the singing when they bring me my birthday dessert!" Mokuba laughed. A child-like glimmer danced in his eyes.

"Then I can't lose, can I? I won't go easy on you."

Mokuba slipped into the car. "Wouldn't expect you to."

They probably should have wore helmets, Kaiba thought as he slipped onto leather seats. All he could only see a five year old, head barely over the steering wheel, when he turned to look at Mokuba through the window. The moment he taught Mokuba to ride a bicycle washed over him. He had fallen over and skinned his knee, crying for help.

Mokuba had already blasted ahead of him when he broke from that reverie, a war cry bellowing from the opened windows.

Kaiba's foot slammed into the clutch, and the gas, and the car was forced into sixth gear as soon he could muster it—he didn't want to disappoint his baby brother by letting him win.

Even if that was the plan.

—

5:49 PM

"Arcade before dinner," Mokuba said after a quick lunch.

Any air-headed demand could have been met, Mokuba knew. It was an unspoken sort of rule. The reason they had been in Singapore when he turned twelve. The object wasn't on how much money could be spent, but how many minutes could be crammed together, made longer. Savoured.

Victory wasn't even on Mokuba's mind as he pounded on the arcade cabinet's console in the KaibaLand facility. Kaiba was at his side leaned in, intensity dotting his eyes, but he was calm and direct nonetheless. Yugi, Jounouchi, and Honda flanked the sides, shouting their praises and their jeers.

"Take that rich-boy!" Jounouchi said, standing just close enough to Kaiba to make the executive shift his stance. "Get 'em birthday boy! Get 'em. Get 'em. Go, go!"

Others wandered in the background, glimpses of profiles of friends that brought up a smile on Mokuba's face. They all milled about, made small talk, played with the younger kids that ran at their heels and dragged parents behind. The place could have been corded off from everyone, a private affair, friends only. But Mokuba liked the raucous chaos in the arcade. The lights and the sounds, the laughing and the screaming.

Because he felt just as little and just as fierce. He wasn't alone, either. He could look over at Kaiba in a lull and see a competitive ten-year old, just as entranced by the setting, with big, blue, determined eyes and his tongue poked out of the corner of his mouth.

'You lose' flashed across Kaiba's screen, and Jounouchi grabbed his shoulders, shaking him. "Ha! He got ya there! He been practicin' with me. How does that feel?"

The blazer Kaiba wore was torn off, throwing Jounouchi's hands away. The blond clutched it, unsure of what to do with it. "Oooh, gettin' serious there, Kaib'?"

"Best two of three, nii-sama?" Mokuba challenged. He wasn't about to let Kaiba's intense fervour go.

The brunet nodded, flowing back to a calm exterior, actively trying to block Jounouchi out. "If that's what you want. We have an hour until reservations."

"Plenty 'a time for him t' kick your ass," Jounouchi said.

Kaiba shoved Jounouchi. The blazer was thrown on the floor in protest. Mokuba giggled.

—

7:26 PM

It wasn't the nicest restaurant in Domino, but Mokuba had declared it had the best dessert in the city, which was all that Kaiba needed to know when making dinner reservations. He already had the seating planned, the variable number of guests in mind.

The group sat at a round table towards the back corner of the room, plates stacked around and pushed off to the side where the food was finished. The conversations were loud and overlapped, Mokuba refusing to sit as the guest of honour, bouncing from spot to spot, talking to everyone while they gave him small gifts and cards, congratulations and best wishes. Stealing drinks from Kaiba's champagne glass every time he passed by, overlooked but noted. All the gifts were piled in his chair for later, after all of dinner was done.

Kaiba slipped the folded letter out of his jacket and into the pile with the rest of the cards.

These acquaintances—Yugi's nerd herd—weren't necessary for this day, but Kaiba would be damned if they hadn't been alerted ahead of time, just in case Mokuba asked for them. Because while Kaiba knew it was selfish that he wanted to grab and claim his little brother and let no one else share him on this day, there wasn't anything, _anything_ he wouldn't do to keep the ear-to-ear smile slapped across Mokuba's face.

And the sight of his eyes, big and round and glowing as the staff walked across the floor, a chiffon cake held out in front of them with sparklers for candles, sizzling and popping, bringing light to the dimmed dining room, was worth killing for, too.

Kaiba pushed his chair out and stood, the champagne fluke raised in one hand like a toast, the other ducked in his pocket, balled into a fist. As the cake was set down, a nervous flutter came into his chest. Eighteen candles may have been on it, glittering, but the boy that sat down in front of it was the same that became enamoured by a cake built out of sand, the best that a penniless Seto could muster, when Mokuba was barely old enough to understand what his birthday was.

" _Happy birthday to you—"_ Kaiba began, focused only on Mokuba, but noticing that the rest of group had followed his lead, standing, singing, off-key and laughing at each other. Mokuba's hands ran through his bangs while his cheeks darkened with blush. They had barely finished when he blew the sparklers out, plucking each of them away so he could get to the cake, taking a bite before the staff could cut it for anyone else present.

The moment that Mokuba sat for the cake was a moment only, and once the slices were passed out to each place setting, he was back to bustling around. The cards and gifts were rounded up in his hands, and he cycled through them as he reached each person, opening it in front of them while leaning on the back of their chair.

Left alone at the back of the table, Kaiba pulled the locket out from under his shirt and opened it. His thumbnail ran along Mokuba's rounded face, the space creased and well-worn from being touched so often.

And then he looked up to Mokuba. That round face was still there, but filled with high cheekbones and a sharper jawline. He was all limbs, thin as a rail no matter how much he ate, and he stood as tall as Jounouchi, who pulled him into a headlock to take a picture once the blond's gift (a Duel Monsters keychain "for the new car I know ya jus' got!" Jounouchi had said) was opened.

He watched as Mokuba was corralled together with Honda, Anzu, and Shizuka, their phones raised up to take a group selfie, flashing faux gang signs and making exaggerated faces. Yugi soon joined in, trying to pull the shy Bakura over as well.

"Weird, ain't it?" Kaiba flinched, inward, and snapped the locket closed. Jounouchi hovered over top of his chair, leaning on the back of it. "For you especially."

"What are you going on about?" Kaiba asked. The locket was tucked away, the champagne glass stolen up.

Mokuba threw his arm over Shizuka's shoulders, and it was just the two of them for a moment, flashing peace signs. "Them. Seein' 'em get all big an' independent an' not havin' to fight their battles anymore."

The rest of the champagne was downed in one drink. "Mokuba's always been independent."

"Yeah, right," Jounouchi snorted. Kaiba glared up him. "Kid's been at yer coattails forever. If I see you in some press thing, I see him."

"Do you have a point?" Kaiba asked, fingers playing with the stem of the glass, wishing it full again.

"It's okay t' let go," Jounouchi said. "He ain't gonna float away. He ain't gonna die. So lighten up. Smile, take pictures with us. He's gonna come runnin' t' you the moment he needs some help. That's what big brothers are for."

Kaiba found himself searching for words, jaw ticked and eyes forward. "It's more than that," he admitted. Over the years, he'd developed a reluctant rapport with Jounouchi, a friendly but strange bond, especially with Mokuba's growing closeness to Shizuka.

"I figured. He don't call ya 'nii-sama' an' mean it the same way Shizuka calls me 'nii-chan'. Figured that one out a long time ago..." Jounouchi said, patting Kaiba's shoulder. They were rolled, pushing Jounouchi away, but loosening as his hands settled in his lap. "My mom an' me didn't get along, ya know. But hell if she didn't get all teary an' snotty when I turned eighteen. An' don't even get me started on Shi-chan..."

"Stop talking."

"Whatever man," Jounouchi said, laughing. He pulled out his phone, scrolling through all the pictures taken for the night. "I'll send ya all the pics I've taken. I know ya want 'em." Kaiba smirked, a quick glance up to Jounouchi, not admitting that the mutt was right. "Your welcome."

The blond shifted out of the way as Mokuba came barrelling up, the letter the last thing in his hand. It was still unopened. He laid it in Kaiba's lap, and was regarded with a quizzical brow. "Later, nii-sama," he whispered. "C'mon, get up, me and you need to take a pic."

"It's not going on your Instagram page."

"Nope," Mokuba said, the flash going off he leaned in close. "It's going on the corporate one."

"Mokuba..."

"One more."

It felt like little hands tugged on Kaiba's arm, urging him to stand. The group had descended upon them, with Kaiba somewhere in the middle of them, ignoring their closeness while Mokuba sought out a waiter to take the group picture for them.

Kaiba slipped his arm over Mokuba's shoulder, urging on a polite smile and pushing Mokuba as close as possible, resisting the urge to smother him in a hug as the younger brother reached up and behind Kaiba's head to make rabbit ears.

—

11:52 PM

Mokuba hadn't opened the letter. It sat on his bed, surrounded by all the other cards and gifts. After they'd gotten home, he'd ran to his room, setting everything up for a few more pictures as he updated social media with what felt like a thousand images, some of which Jounouchi, Anzu, and Yugi had sent him.

There were so many messages from his fan club. Best wishes received all day from different office associates, other corporate heads e-mailing him politely. He had lost track of time in the process, sitting cross-legged on his bed.

And the letter sat there in the middle, still unopened, but not forgotten.

Mokuba waited until everything else was finished, with the last minutes ticking away on the day, before opening up the letter.

 

_Mokuba,_

_This letter has been started a thousand times, perhaps from the moment I realised that this day had to come. Maybe I just imagined that it never would, no matter how illogical it sounds. As if we could, somehow, live in a perpetual daydream where you're still small enough to hide behind my legs and make a cape out of my coattails._

_We could build a virtual reality and live in it, never aging. No. That would be ridiculous. It would mean that I regret you growing older, and I absolutely don't._

_Today, you are a man. If you want to be._

_You don't have to be anything you don't want, however. But you know that._

_Just as I know you don't subscribe yourself to anything traditional. How could you? You've lived in such an odd convention that I don't know how you managed to be so normal, to ask for the simpler things in life. You enjoy the moments, not the things. I spoiled you silly because I never wanted you to never know what the word 'need' was. I wanted you to stand tall, be proud, have a role-model, though maybe not always the best one. I anticipated every kind of connotation that upbringing could have produced. You took it with such beautiful stride._

_You are impossibly selfless, perfectly flawed, and wonderfully talented. The world is at your knees if you beg it be, but in the end I have a feeling you'll just make it your friend. Something you've excelled at, a trait you've managed to learn despite having the least qualified person to set an example as you've been led into adulthood._

_Now that you're here, whatever path you take ahead of you is yours for the making. Even if that means throwing away any titles or worldly possessions and becoming a hermit. Just know that there is always someone at your back, supporting your choices. And a warm bed, and arms, waiting for you if you choose to come back._

_There are no expectations, there never have been. I've never urged you to do anything you didn't want; you chose everything on your own. You have such a strong head on your shoulders. Which I suppose is why there was a ten-year old Vice President who could strike fear in the hearts of board members. I hope you don't resent that strange upbringing. I didn't really have a guidebook on how to rear you into the adult that you're about to become. But I know you'll be a great one._

_There's so much time ahead of you. I look forward to the great things you'll accomplish. I can't wait to see what they'll be._

_I love you, and I'm so very proud of you._

 

Mokuba wandered the hall as read, barely minding the bannister when his elbow crashed into it on the way down the stairs. "Nii-sama?" He asked, soft, as he went into the parlour.

Kaiba sat on the couch, phone in hand, scrolling through the same pictures Mokuba had just been posting. He seemed oblivious to the outside world, lost in his own thoughts, but Mokuba knew better. A hand went up to Kaiba's face, fingers sliding down and pushing away what Mokuba could only assume were tears that he didn't want his little brother to see.

Mokuba plopped by him, the letter still in hand, crinkled as his fingers pressed into it. His body slumped up against Kaiba's side. The brunet moved his arm about, putting it over Mokuba's shoulders. "I had fun today," Mokuba said. "Did you?"

"Of course," Kaiba replied. He set the phone down and looked over, seeing where Mokuba held the letter. A deep breath was sucked in.

"You okay?" Mokuba asked.

"I am. Happy birthday, Mokuba."

"Thanks, nii-sama," he said, sliding down further as if to make his brother into a pillow while he closed his eyes. "For everything."

And Kaiba smiled.

**Author's Note:**

> Fukushachou - Vice President, basically.


End file.
